If xy > 0, does (x - 1)(y - 1) = 1 ?

(1) x + y = xy

(2) x = y

Michael arranged all his books in a bookcase with 10 books on each shelf and no books left over. After Michael acquired 10 additional books, he arranged all his books in a new bookcase with 12 books on each shelf and no books left over. How many books did Michael have before he acquired the 10 additional books?

(1) Before Michael acquired the 10 additional books, he had fewer than 96 books.

(2) Before Michael acquired the 10 additional books, he had more than 24 books.

Is x² greater than x ?

(1) x² is greater than 1.

(2) x is greater than -1.

What is the value of xy ?

(1) x + y = 10

(2) x - y = 6

If m and n are nonzero integers, is mⁿ an integer?

(1) n^m is positive.

(2) n^m is an integer

Is x between 0 and 1 ?

(1) x² is less than x.

(2) x³ is positive.

After winning 50 percent of the first 20 games it played, Team A won all of the remaining games it played. What was the total number of games that Team A won?

(1)Team A played 25 games altogether.

(2) Team A won 60 percent of all the games it played.

If x² + y² = 29, what is the value of (x - y)² ?

(1) xy = 10

(2) x = 5

K is a set of numbers such that

(i) if x is in K, then -x is in K, and

(ii) if each of x and y is in K, then xy is in K. Is 12 in K ?

(1) 2 is in K.

(2) 3 is in K.

If x, y, and z are positive numbers, is x > y > z ?

(1) xz > yz

(2) yx > yz